Alfvén wave heating of a cylindrical plasma using axisymmetric waves. Part 2. Kinetic theory

1986 ◽  
Vol 35 (1) ◽  
pp. 75-106 ◽  
Author(s):  
I. J. Donnelly ◽  
B. E. Clancy ◽  
N. F. Cramer
Keyword(s):  
Kinetic Theory ◽  
Wave Equations ◽  
Compressional Wave ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Electrostatic Wave ◽  
Hot Plasma ◽  
Wave Heating ◽  
Ion Cyclotron ◽  
Consequent Increase

Kinetic theory, including ion Larmor radius effects, is used to analyse the Alfvén wave heating of cylindrical plasmas using axisymmetric waves excited by an antenna at frequencies up to the ion cyclotron frequency. At the Alfvén resonance position, the compressional wave is mode converted to a quasi-electrostatic wave (QEW) which propagates towards the plasma centre or edge depending on whether the plasma is hot or warm. The energy absorbed by the plasma agrees with the MHD theory predictions provided the QEW is heavily damped before reaching the plasma centre or edge; if it is not, then QEW resonances may occur with a consequent increase in antenna resistance. The relation between ion cyclotron wave resonances and QEW resonances in a hot plasma is shown. The behaviour described above is demonstrated by numerical solution of the wave equations for small and large tokamak-like plasmas. WKB theory has been used to derive useful expressions which quantify the QEW behaviour.

Kinetic theory of Alfvén waves in plasmas with force-free currents

1991 ◽  
Vol 45 (2) ◽  
pp. 213-228 ◽  
Author(s):  
I. J. Donnelly ◽  
B. E. Clancy
Keyword(s):  
Kinetic Theory ◽  
Small Amplitude ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Alfvén Waves ◽  
Plasma Current ◽  
Theory Analysis ◽  
Wave Heating ◽  
Reversed Field

Equations are derived for the kinetic-theory analysis of small-amplitude Alfvén waves in cylindrical plasmas carrying force-free currents. The equations, which include ion Larmor-radius effects to second order, are applicable to reversed-field pinches as well as to tokamaks. Fourier mode amplitudes are derived for model antennas with radial current feeds, and a quantitative analysis is made of the antenna resistance and the wave density fields in a small tokamak during Alfvén-wave heating. The effect of the plasma current on the wave thermal energy flux is discussed.

scholarly journals Plasma Heating by Alfvén Waves - Kinetic Properties of Magnetohydrodynamic Disturbances

1985 ◽  
Vol 107 ◽  
pp. 381-389
Author(s):  
Akira Hasegawa
Keyword(s):  
Electric Field ◽  
Plasma Heating ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Alfvén Waves ◽  
Kinetic Properties ◽  
Parallel Electric Field ◽  
Astrophysical Plasmas ◽  
Finite Larmor Radius ◽  
Wave Heating

Mechanisms of Alfvén wave heating in space-astrophysical plasmas are presented with particular emphasis on the parallel electric field generated in the magnetohydrodynamic perturbations due to the finite Larmor radius effects.

scholarly journals Physics of kinetic Alfvén waves: a gyrokinetic theory approach

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Liu Chen ◽  
Fulvio Zonca ◽  
Yu Lin
Keyword(s):  
Kinetic Theory ◽  
Short Wavelength ◽  
Spectral Feature ◽  
Transport Processes ◽  
Alfven Wave ◽  
Wave Number ◽  
Larmor Radius ◽  
Theory Approach ◽  
Background Magnetic Field ◽  
Linear And Nonlinear

AbstractThe transverse shear Alfvén wave (SAW) is a fundamental anisotropic electromagnetic oscillation in plasmas with a finite background magnetic field. In realistic plasmas with spatial inhomogeneities, SAW exhibits the interesting spectral feature of a continuous spectrum. That is, the SAW oscillation frequency varies in the non-uniform (radial) direction. This continuum spectral feature then naturally leads to the phase-mixing process; i.e., time asymptotically, the effective radial wave-number increases with time. Any initial perturbation of SAW structures will, thus, evolve eventually into short-wavelength structures; termed as kinetic Alfvén wave (KAW). Obviously, one needs to employ kinetic theory approach to properly describe the dynamics of KAW; including effects such as finite ion-Larmor radius (FILR) and/or wave–particle interactions. When KAW was first discovered and discussed in 1975–1976, it was before the introduction of the linear electromagnetic gyrokinetic theory (1978) and nonlinear electromagnetic gyrokinetic theory (1982). Kinetic treatments then often involved the complicated procedures of taking the low-frequency limit of the Vlasov kinetic theory and/or employing the drift-kinetic theory approach; forsaking, thus, the FILR effects. In recent years, the powerful nonlinear gyrokinetic theory has been employed to re-examine both the linear and nonlinear physics of KAWs. This brief review will cover results of linear and nonlinear analytical theories, simulations, as well as observational evidences. We emphasize, in particular, that due to the enhanced electron–ion de-coupling in the short-wavelength regime, KAWs possess significantly enhanced nonlinear coupling coefficients and, thereby, play important roles in the heating, acceleration, and transport processes of charged particles in magnetized plasmas.

scholarly journals Compressional Alfvén Wave Propagation Below Ion Cyclotron Frequency

1968 ◽  
Vol 21 (2) ◽  
pp. 129 ◽  
Author(s):  
RC Cross ◽  
JA Lehane
Keyword(s):  
Wave Propagation ◽  
Cyclotron Resonance ◽  
Cyclotron Frequency ◽  
Cutoff Frequency ◽  
Compressional Wave ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Ion Cyclotron Resonance ◽  
Wave Measurements ◽  
Ion Cyclotron

When the compressional wave cutoff frequency is below ion cyclotron frequency both compressional and torsional Alfven waves may be present simultaneously. Oompressional wave measurements in this regime are particularly important because of their relevance to certain ion cyclotron resonance heating experiments. This paper extends the work of others in this important regime.

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